Field of the Invention
Embodiments of the present disclosure relate to the field of X or Gamma ray security inspection, and particularly, to an X or Gamma ray inspection system for inspecting an object such as a container or vehicle, and an alignment system and an alignment method for the inspection system.
Description of the Related Art
Term “three points on one line” relates to a target spot of an accelerator, a central line of a detector tip, a central line of a collimator which are coplanar, and adjustments of “three points on one line” are intended to ensure that the target spot of the accelerator, the central line of the detector tip, and the central line of the collimator (sometimes including a central line of a calibrating device and the like) are located in one reference plane, as shown in FIG. 1.
In an existing measurement method, alignment of the target spot of the accelerator, the central line of the detector tip, and the central line of the collimator is manually measured by using a laser theodolite. A vertical line of a reticle of the theodolite is arranged to coincide with central lines of detectors on upper and lower ends of a detector vertical arm, and to align with a center of the target spot as far as possible. This method is implemented through the human eye, and thus is insufficient in objectivity and accuracy, that is, is easily and greatly affected by placement and debugging of instruments and the visual sense of the measurer.
Further, a detector arm mount is generally used in many existing movable inspection systems, and needs to be unfolded quickly for operation after these movable inspection systems reach a new inspection site. However, the detector arm or mount, as a mechanical structure, needs to be further adjusted so that the ray source, the collimator and the detector are located within one plane. Thus, there is a need to alignment system and method enabling accurate, quick and reliable alignment.